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The 2012–2016 eruptive cycle at Copahue volcano (Argentina) versus the peripheral gas manifestations: hints from the chemical and isotopic features of fumarolic fluids


This study presents the chemical and isotopic compositions of hydrothermal gases from fumaroles discharging around Copahue volcano (Argentina). Gas samples, including those from two fumaroles at the active summit crater, were collected during 13 surveys carried out by different research teams from 1976 to February 2016. The time-series of H2, CO and light hydrocarbons showed episodic increases related to the main events of the last eruptive cycle that started on 19 July 2012. Concentration peaks were likely caused by enhanced input of hot magmatic fluids affecting the hydrothermal reservoir. These data contrast with the temporal variations shown by Rc/Ra and δ13C-CO2 values in 2012–2014, which indicated an increasing input from a crustal fluid source. In 2015–2016, however, these isotopic parameters showed opposite trends; their composition became closer to that of the two summit fumaroles, which possibly corresponds to that of the deep magmatic-related end-member. The delayed and reduced compositional changes in the peripheral hydrothermal fluid discharge in response to the 2012–2016 eruptive events suggest that geochemical surveys of these emissions are unlikely to provide premonitory signals of volcanic unrest if the volcanic activity remains centered in the main crater. Instead, an instrument which is able to provide measurements of volcanic gases in the air (e.g. MultiGAS) may be used to detect changes at the summit crater. Otherwise, monitoring of seismic activity and ground deformation, as well as the periodic measurement of the chemistry of the water in the Rio Agrio, which is fed by thermal discharge from the summit crater, seem to represent the most reliable means of monitoring at Copahue. However, the relative compositional stability of the hydrothermal reservoir is a great advantage in terms of geothermal resource exploitation and could encourage new investments in the Copahue geothermal project which was abandoned in the 1990s.

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  1. Agusto M, Varekamp J (2016) The Copahue hydrothermal system and applications for volcanic surveillance. In: Tassi F, Vaselli O, Caselli A (eds) Copahue, active volcanoes of the world. Springer Verlag-Berlin, Heidelberg, pp 199–238

  2. Agusto M, Tassi F, Caselli AT, Vaselli O, Rouwet D, Capaccioni B, Caliro S, Chiodini G, Darrah T (2013) Gas geochemistry of the magmatic-hydrothermal fluid reservoir in the Copahue-Caviahue Volcanic Complex (Argentina). J Volcanol Geotherm Res 257:44–56

  3. Aiuppa A, Federico C, Guiudice G, Guiuffrida G, Guida R, Gurrieri S, Liuzzo M, Moretti R, Papa P (2009) The 2007 eruption of Stromboli volcano: insights from real-time measurement of the volcanic gas plume CO2/SO2 ratio. J Volcanol Geotherm Res 182:221–230

  4. Capaccioni B, Tassi F, Vaselli D, Tedesco D, Rossi PML (2005) The November 2002 degassing event at Panarea Island (Italy): the results of a 5 months geochemical monitoring program. Ann Geophys 48:755–765

  5. Capaccioni B, Tassi F, Vaselli O, Tedesco D, Poreda R (2007) Submarine gas burst at Panarea Island (southern Italy) on 3 November 2002: a magmatic versus hydrothermal episode. J Geophys Res 112:B05201

  6. Capaccioni B, Rouwet D, Tassi F (2016) Cl degassing from extremely acidic crater lakes: preliminary results from experimental determinations and implications for geochemical monitoring. In: Obha T, Capaccioni B, Caudron C (eds) Geol Soc London Special Publ 437. https://doi.org/10.1144/SP437.12

  7. Caselli AT, Agusto M, Velez ML, Forte P, Bengoa C, Capaccioni B (2016a) The 2012 eruption. In: Tassi F, Vaselli O, Caselli A (eds) Copahue, active volcanoes of the world. Springer Verlag-Berlin, Heidelberg, pp 61–77

  8. Caselli AT, Liccioli C, Tassi F (2016b) Risk assessment and mitigation at Copahue volcano. In: Tassi F, Vaselli O, Caselli A (eds) Copahue, active volcanoes of the world. Springer Verlag-Berlin, Heidelberg, pp 239–254

  9. Caselli AT, Velèz ML, Agusto M, Liccioli C, Vaselli O (2016c) Prehistoric to historic volcanic activity at Copahue volcano. In: Tassi F, Vaselli O, Caselli A (eds) Copahue, active volcanoes of the world. Springer Verlag-Berlin, Heidelberg, pp 49–59

  10. Cembrano J, Hervé F, Lavenu A (1996) The Liquiñe Ofqui fault zone: a long-lived intra-arc fault system in southern Chile. Tectonophysics 259:55–66

  11. Cembrano J, Lavenu A, Reynolds P, Arancibia G, López G, Sanhueza A (2002) Late Cenozoic transpressional ductile deformation north of the Nazca-South America-Antarctica triple junction. Tectonophysics 354:289–314

  12. Chiodini G, Marini L (1998) Hydrothermal gas equilibria: the H2O-H2-CO2-CO-CH4 system. Geochim Cosmochim Acta 62(15):2673–2687

  13. Chiodini G, Cioni R, Marini L, Panichi C (1995) Origin of the fumarolic fluids of Vulcano Island, Italy and implications for volcanic surveillance. Bull Volcanol 57:99–110

  14. Craig H (1961) Isotopic variations in meteoric waters. Science 133:1702–1703

  15. CRC (2001) In: Lide DR (ed) Handbook of chemistry and physics, 82nd edn. CRC Press, Boca Raton LLC

  16. de Moor JM, Aiuppa A, Avard G, Wehrmann H, Dunbar N, Muller C, Tamburello G, Giudice G, Liuzzo M, Moretti R, Conde V, Galle B (2016a) Turmoil at Turrialba Volcano (Costa Rica): degassing and eruptive processes inferred from high-frequency gas monitoring. J Geophys Res Solid Earth 121:5761–5775

  17. de Moor JM, Aiuppa A, Pacheco J, Avard G, Kern C, Liuzzo M, Martinez M, Giudice G, Fischer TP (2016b) Short period volcanic gas precursors to phreatic eruptions: insights from Poás Volcano. Costa Rica. Earth Planet Sci Lett 442:218–227

  18. Deines P, Langmuir D, Herman RS (1974) Stable carbon isotope ratio and the existence of a gas phase in the evolution of carbonate groundwaters. Geochim Comoschim Acta 38:1147–1164

  19. Evans W, White L, Rapp J (1998) Geochemistry of some gases in hydrothermal fluids from the southern Juan de Fuca Ridge. J Geophys Res 15:305–313

  20. Farley KA, Neroda E (1998) Noble gases in the Earth’s mantle. Annu Rev Earth Planet Sci 26:189–218

  21. Fischer TP, Arehart GB, Sturchio NC, Williams SN (1996) The relationship between fumarole gas composition and eruptive activity at Galeras Volcano (Colombia). Geology 24:531–534

  22. Fischer TP, Hilton DR, Zimmer MM, Shaw AM, Sharp ZD, Walker JA (2002) Subduction and recycling of nitrogen along the Central American margin. Science 297:1154–1157

  23. Fischer TP, Ramìrez C, Mora-Amador RA, Hilton DR, Barnes JD, Sharp ZD, Le Brun M, de Moor JR, Barry PH, Füry E, Shaw AM (2015) Temporal variations in fumarole gas chemistry at Poás volcano, Costa Rica. J Volcanol Geotherm Res 294:56–70

  24. Folguera A, Introcaso A, Giménez M, Ruiz F, Martinez P, Tunstall C, García Morabito E, Ramos VA (2007) Crustal attenuation in the Southern Andean retroarc (38°–39°30′ S) determined from tectonic and gravimetric studies: the Lonco-Luán asthenospheric anomaly. Tectonophysics 239:129–147

  25. Folguera A, Rojas Vera E, Vélez L, Tobal J, Orts D, Agusto M, Caselli A, Ramos VA (2016) A review of the geology, structural controls, and tectonic setting of Copahue volcano, Southern Volcanic Zone, Andes, Argentina. In: Tassi F, Vaselli O, Caselli A (eds) Copahue, active volcanoes of the world. Springer Verlag-Berlin, Heidelberg, pp 3–22

  26. Forte P, Bengoa C, Caselli A (2012) Análisis preliminar de la actividad sísmica del complejo volcánico Copahue-Caviahue mediante técnicas de array. Proceed. XIII Congreso Geológico Chileno, Antofagasta, pp 574–576

  27. Giggenbach WF (1987) Redox processes governing the chemistry of fumarolic gas discharges from White Island, New Zealand. Appl Geochem 2:143–161

  28. Giggenbach WF (1992) Isotopic shifts in waters from geothermal and volcanic systems along convergent plate boundaries and their origin. Earth Planet Sci Lett 113:495–510

  29. Giggenbach WF (1996) Chemical composition of volcanic gases. In: Scarpa R, Tilling R (eds) Monitoring and mitigation of volcano hazard. Springer-Verlag, Berlin, pp 222–256

  30. Giggenbach WF, Sano Y, Wakita H (1993) Isotopic composition of helium, and CO2 and CH4 contents in gases produced along the New Zealand part of a convergent plate boundary. Geochim Cosmochim Acta 57:3427–3455

  31. Graham DW (2002) Noble gas isotope geochemistry of mid-ocean ridge and ocean island basalts: characterization of mantle source reservoirs. Rev Mineral Geochem 47:247–318

  32. Hilton DR, McMurtry GM, Goff F (1998) Large variations in vent fluid CO2/3He ratios signal rapid changes in magma chemistry at Loihi Seamount, Hawaii. Nature 396:359–362

  33. Hilton DR, Fischer TP, Marty B (2002) Noble gases in subduction zones and volatile recycling. In: Porcelli D, Ballentine C, Wieler R (eds) Noble gas in Geochemistry and Cosmochemistry. Mineral Soc Am Spec 47:319-370

  34. Hilton DR, Ramirez CJ, Mora-Amador R, Fischer TP, Füri E, Barry PH, Shaw AM (2010) Monitoring of temporal and spatial variations in fumarole helium and carbon dioxide characteristics at Poàs and Turrialba volcanoes, Costa Rica (2001–2009). Geochem J 44:431–440

  35. Javoy M, Pineau F, Iiyama I (1978) Experimental determination of the isotopic fractionation between gaseous CO2 and carbon dissolved in tholeiitic magma; a preliminary study. Contrib Mineral Petrol 67:35–39

  36. JICA (Japan International Cooperation Agency) (1992) The feasibility study on the Northern Neuquén Geothermal Development Project. Ente Provincial de Energia de la Provincial del Neuquén, pp 89 (in Spanish)

  37. Jurío RL (1977) Características geoquímicas de los fluidos termales de Copahue (Neuquén, Argentina). Principales implicancias geotérmicas. Minería 172:1–11 (in Spanish)

  38. Khilyuk LF, John O, Robertson JO Jr, Endres B, Chilingarian GV (2000) Gas migration: events preceding earthquakes, 1st edn. Gulf Professional Publishing, Houston, p 400

  39. Mamyrin B, Tolstikhin I (1984) Helium isotopes in nature. In: Fyfe W (ed) Development in geochemistry. Elsevier, Amsterdam, p 288

  40. Martini M, Bermudez A, Delpino D, Giannini L (1997) The thermal manifestations of Copahue volcano area. Neuquen, Argentina. Proceed. VIII Congreso Geologico Chileno, Antofagasta, Chile, 1:352–356

  41. Mas LC, Mas GR (2016) Geothermal energy development at Copahue volcano. In: Tassi F, Vaselli O, Caselli A (eds) Copahue, active volcanoes of the world. Springer Verlag-Berlin, Heidelberg, pp 257–271

  42. Melián G, Tassi F, Pérez N, Hernández P, Sortino F, Vaselli O, Padrón E, Nolasco D, Barrancos J, Padilla G, Rodríguez F, Dionis S, Calvo D, Notsu K, Sumino H (2012) A magmatic source for fumaroles and diffuse degassing from the summit crater of Teide Volcano (Tenerife, Canary Islands): a geochemical evidence for the 2004–2005 seismic–volcanic crisis. Bull Vulcanol 74:1465–1483

  43. Melnick D, Folguera A, Ramos V (2006) Structural control on arc volcanism: the Caviahue-Copahue complex, central to Patagonian Andes transition (38°S). J S Am Earth Sci 22:66–88

  44. Menyailov IA, Nikitina LP, Shapar VN, Pilipenko VP (1986) Temperature increase and chemical change of fumarolic gases at Momotombo Volcano, Nicaragua, in 1982–1985; are these indicators of a possible eruption? J Geophys Res B 91(12):12199–112214

  45. Montegrossi G, Tassi F, Vaselli O, Buccianti A, Garofalo K (2001) Sulfur species in volcanic gases. Anal Chem 73:3709–3715

  46. Ozima M, Posodek FA (1983) Noble gas geochemistry. Cambridge University Press, Cambridge

  47. Padron E, Perez NM, Hernandez PA, Sumino H, Melian G, Barrancos J, Nolasco D, Padilla G, Dionis S, Rodriguez F, Hernandez I, Calco D, Peraza MD, Nagao K (2013) Diffusive helium emissions as a precursory sign of volcanic unrest. Geology 41:539–542

  48. Panarello HO (2002) Características isotópicas y termodinámicas de reservorio del campo geotérmico Copahue-Caviahue, provincia del Neuquén. Rev Asoc Geol Argent 57(2):182–194

  49. Panarello HO, Levin M, Albero MC, Sierra JL, Gingins MO (1988) Isotopic and geochemical study of the vapour dominated geothermal field of Copahue (Neuquén, Argentina). Rev Bras Geofís 5(2):275–282

  50. Pesicek J, Engdahl E, Thurber C, DeShon H, Lange D (2012) Mantle subducting slab structure in the region of the 2010 M8.8 Maule earthquake (30–40°S), Chile. Geophys J Int 191:317–324

  51. Petrinovic IA, Villarosa G, Délia L, Guzmán SP, Páez GN, Oues V, Manzoni C, Delménico A, Balbis C, Carniel R, Hernando IR (2014) La erupción del 22 de diciembre de 2012 del volcán Copahue, Neuquén, Argentina: caracterización del ciclo eruptivo y sus productos. Rev Asoc Geol Argent 71:161–173

  52. Poreda RJ, Craig H (1989) Helium isotope ratios in circum-Pacific volcanic arcs. Nature 338:473–478

  53. Radic J (2010) Las cuencas cenozoicas y su control en el volcanismo de los complejos Nevados de Chillán y Copahue-Callaqui (36°–39°S). Andean Geol 37(1):220–246

  54. Rizzo A, Barberi F, Carapezza ML, Di Piazza A, Francalanci L, Sortino F, D’Alessandro W (2015) New mafic magma refilling a quiescent volcano: evidence from He-Ne-Ar isotopes during the 2011–2012 unrest at Santorini, Greece. Geochem Geophys Geosyst 16(3):798–814

  55. Sano Y, Fischer TP (2013) The analysis and interpretation of noble gases in modern hydrothermal systems. In: Burnard P (ed) Noble gases as geochemical tracers. Series: advances in isotope geochemistry. Springer Verlag, Heidelberg, pp 249–317

  56. Sano Y, Marty B (1995) Origin of carbon in fumarolic gas from island arcs. Chem Geol 119:265–274

  57. Sano Y, Williams SN (1996) Fluxes of mantle and subducted carbon along convergent plate boundaries. Geophys Res Lett 23:2749–2752

  58. Shaw AM, Hilton DR, Fischer TP, Walker JA, Alvarado G (2003) Contrasting He-C relationships in Nicaragua and Costa Rica: insights into C cycling through subduction zones. Earth Planet Sci Lett 214:499–513

  59. Stern CR (2004) Active Andean volcanism: its geologic and tectonic setting. Rev Geol Chile 31(2):161–206

  60. Stoibert J, Rose W (1970) The geochemistry of Central-American volcanic gas condensates. Geol Soc Am Bull 81:2891–2912

  61. Symonds RB, Mizutani Y, Briggs PH (1996) Long-term geochemical surveillance of fumaroles at Showa-Shinzan dome, Usu volcano, Japan. J Volcanol Geotherm Res 73:177–211

  62. Symonds RB, Gerlach TM, Reed MH (2001) Magmatic gas scrubbing: implications for volcano monitoring. J Volcanol Geotherm Res 108:303–341

  63. Tamburello G, Agusto M, Caselli A, Tassi F, Vaselli O, Calabrese S, Rouwet D, Capaccioni B, Di Napoli R, Cardellini C, Chiodini G, Bitetto M, Brusca L, Bellomo S, Aiuppa A (2015) Intense magmatic degassing through the lake of Copahue volcano, 2013–2014. J Geophys Res Solid Earth 120. https://doi.org/10.1002/2015JB012160

  64. Taran YA, Pokrovsky BG, Esikov AD (1989) Deuterium and oxygen-18 in fumarolic steam and amphiboles from some Kamchatka volcanoes: ‘andesitic waters’. Dokl Akad Nauk SSSR 304:440–443

  65. Tardani D, Reich M, Roulleau E, Takahata N, Sano Y, Péres-Flores P, Sànchez-Alfaro P, Cembrano J, Arancibia G (2016) Exploring the structural controls on helium, nitrogen and carbon isotopes signatures in hydrothermal fluids along an intra-arc fault system. Geochim Cosmochim Acta 184:193–211

  66. Tassi F, Vaselli O, Barbosa V, Fernandez E, Duarte E (2004) Fluid geochemistry and seismic activity in the period 1998–2002 at Turrialba Volcano (Costa Rica). Ann Geophys 47(4):1–11

  67. Tassi F, Agusto M, Vaselli O, Chiodini G (2016) Geochemistry of the magmatic-hydrothermal fluid reservoir of Copahue volcano (Argentina): insights from the chemical and isotopic features of fumarolic discharges. In: Tassi F, Vaselli O, Caselli A (eds) Copahue, active volcanoes of the world. Springer Verlag-Berlin, Heidelberg, pp 119–139

  68. Varekamp JC, Ouimette AP, Kreulen R (2004) The magmato-hydrothermal system of Copahue Volcano, Argentina. In: Wanty RB, Seal RB II (eds) Water-rock interaction, 11. Bakema Publishers, Leiden, pp 215–218

  69. Varekamp JC, Maarten de Moor J, Merrill M, Colvin A, Goss A, Vroon P, Hilton D (2006) Geochemistry and isotopic characteristics of Caviahue-Copahue volcanic complex, province of Neuquen, Argentina. In: Kay S, Ramos A (eds) Evolution of an Andean margin: a tectonic and magmatic view from the Andes to the Neuquen Basin (35°–39°S lat). Geol Soc Am Spec Issue 407:317–342

  70. Vaselli O, Tassi F, Duarte E, Fernandez E, Poreda R, Delgado Huertas A (2010) Evolution of fluid geochemistry at the Turrialba volcano (Costa Rica) from 1998 to 2008. Bull Vulcanol 72(4):397–410

  71. Velez ML, Euillades P, Caselli A, Blanco M, Martínez Díaz J (2011) Deformation of Copahue volcano: inversion of InSAR data using a genetic algorithm. J Volcanol Geotherm Res 202(1–2):117–126

  72. Veléz ML, Euillades P, Blanco M, Euillades L (2016) Ground deformation between 2002 and 2013 from InSAR observations. In: Tassi F, Vaselli O, Caselli A (eds) Copahue, active volcanoes of the world. Springer Verlag-Berlin, Heidelberg, pp 185–198

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Enrico Calvi (CNR-IGG) and Enrico Maria Selmo (University of Parma) are gratefully acknowledged for their help during the isotopic measurements of carbon in CO2 and oxygen and hydrogen, respectively. The authors also thank Dr. Andrea Rizzo and M. Tantillo for the analysis of He isotopes carried out at the INGV laboratories of Palermo (Italy). The authors wish to thank M. de Moore, A. Harris and an anonymous reviewer for their helpful comments and suggestions. This work was carried out in the framework of a general agreement between the University of General Roca (Argentina) and the University of Florence (Italy).

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Correspondence to F. Tassi.

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Tassi, F., Agusto, M., Lamberti, C. et al. The 2012–2016 eruptive cycle at Copahue volcano (Argentina) versus the peripheral gas manifestations: hints from the chemical and isotopic features of fumarolic fluids. Bull Volcanol 79, 69 (2017). https://doi.org/10.1007/s00445-017-1151-7

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  • Geochemical monitoring
  • Copahue volcano
  • Fluid geochemistry
  • Hydrothermal system
  • Active volcano